Hello all I am new to this forum and hoping to find some insight. I have a 98.5 with the following mods,Edge juice with attitude, turbo modified by Gillette diesel, 275 RV injectors AFE intake and 4" turbo back.What i am seeing is some weird temp issues. Truck unloaded sitting at a stop light will start building temp for no reason starts at 180 and sometimes will go up to 190 or higher, ambient temp plays no factor will do it on a 55 deg morning or a 90 deg day. Differnt from one stop light to the next. Took to my local shop that helps me out strapped down to dyno duplicated problem but here is where it gets weird, one pull the truck wont break 190 with a 60% load applied via the dyno next pull truck truck hits 230 easily and once in a great while the truck will puff a tiny cloud of white then right back to black out of the exhaust. Fan clutch cycles normally, coolant shows no signs of combustion contamination not a 53 series block water pump looked great and truck uses absolutley no coolant. Radiator is five years old was clean externaly and passed flow test at the radiator shop earlier today. T-stat is probably 4 years old and this is the 3rd one but last time i replaced it the sympotoms were not like this. Engine has 102k on it and probably gets 3 to 5 k a year on it? i would really appreciate some feedbackThanks in advace

the one befor the oriellys made in isreal or germany was the napa with the same results. what part number did you get? i got the one that cost $27 i think. did not pay attention to the part #. i just want one that works and have not tried the cummins yet. but $70 is alot for a tstat.

I have no idea what part number. I just as for the 180.

  dripley said:

i take the chart pretains to the cummins tstat. wher did you go to get the info with the serial number?

Cummins quickserve

  cajflynn said:

I've towed a little bit with my trucks and the only time my thermostat swings is when its bad or was purchased somewhere other than Napa. My temp stays firmly on 190 when towing unless it is going uphill for a long time. I run the 180 degree tstat. The cummins tstat is a waste of $70 in my opinion. I also change my tstat every 30 to 40k miles.

I only paid $30 ish for a Cummins tstat!

I would by them if they were 30 and came in a 180. I would think the cummins ones come in 190. I live in Florida so I have no need for the 190.

they quoted me 70 bucks for the cummins in Liberal Kansas about 4 months ago.

Cummins should offer a 180 and a 190 as they were both offered stock and all Industrial ISB's use 180's. Not sure why they are so expensive elsewhere?

I've bought 180's from Cummins before an they were like 30 bucks ! I'll call and see what I can get them for today.

the one i had priced was a 190.

Cummins part number in the 180 is 3967195 an is $34.44 part number on 190 is 3946849 an is $69.79Sent from my DROIDX using Tapatalk

i might try the 180 and see how it works. i just cant figure why the 190 should cost 35 bucks more for the 10 more degrees.

Got everything back together and drove her around today. tems seem to be holding under 190 and modulating between 181 and 188. Never used to do this before but atleast it stays under 190. New t-stat chyrsler 180, flushed radiator and intercooler and lookat everything else and could not find any problems. Will rep[ort more as it develops

Good deal!

good to hear. letus know how that tstat works out. did not mean to hijack your thread, just got carried away.

The (best) NAPA stat and 8/10 oz's of RMI25 (to keep the cooling system conditioned).With the age of these ISBs, keep an eye on the core tanks (sides) for leaks and do not waste money trying to make repairs... get a new radiator (you can get a copper core btw).And; if I could only find the shroud to rad clips..!If your fan belt scrubs on one side, look to replacing the tensioner (around 350K). The bearing lasts forever but the spring & arm assembly will ____ (wear out), throwing the pulley off track.pc